Glulam
Glue laminated timber has almost the same load bearing capacity as steel, but a far lower weight and excellent fire resistance due to its charring characteristics. When used in heavy timber construction, Glulam ensures high earthquake resistance and excellent resistance to aggressive substances. Many different 'lay-ups' are possible, arranging higher strength 2x laminations near the top and bottom of beams where the stresses are highest to increase the beams capacity.
Glulam allows a high degree of prefabrication, and long structural spans where necessary - but is equally effective for shorter spans. Its thermal properties help prevent cold bridging.
Glulam beams laid on their flat and used as floor or roof panels are known as GLT panels - see Glue-Laminated Timber Panels.
Up to 2.0m (6.5 ft) deep, or greater with secondary lamination.